The upshot of this is that internal decls in an app target will be in the
generated header but internal decls in a framework target will not. This
is important since the generated header is part of a framework's public
interface. Users always have the option to add members via category to an
internal framework type they need to use from Objective-C, or to write the
@interface themselves if the entire type is missing. Only internal protocols
are left out by this.
The presence of the bridging header isn't a /perfect/ way to decide this,
but it's close enough. In an app target without a bridging header, it's
unlikely that there will be ObjC sources depending on the generated header.
Swift SVN r19763
...and just outright import the bridging header if that's what's needed.
This means we'll use @class and @protocol whenever we're just using a class
or protocol in a type, but still import the enclosing module when we need
the definition. We'll also fall back to the module (or bridging header) if
we need something /else/ from C: a struct, a typedef, whatever.
<rdar://problem/17183425>
Swift SVN r18795
